1. Field of the Invention
The invention is related to systems and methods for measuring shear stress-strain response, and more specifically, to systems and methods for measuring shear stress-strain response for structures that include thick adhesive bondlines.
2. Description of the Related Art
The standard method (ASTM D5656) that is typically used to measure the shear stress-strain response for thin adhesive bondlines (e.g., having bondline thicknesses of 0.005 to 0.020 in or 0.127 to 0.508 mm) employs the American Cyanamid KGR-1 gage. One improvement to ASTM D5656 has been proposed in Yang et al., “Evaluation and Adjustments for ASTM D5656 Standard Test Method for Thick-Adherend Metal Lap-Shear Joints for Determination of the Stress-Strain Behavior of Adhesives in Shear by Tension Loading,” Journal of Testing and Evaluation, JTEVA, volume 29, no. 1, January 2001, pp. 36-43. In this article, the authors set forth an arrangement that uses four pins and mounting holes to mount a KGR-1 device to a test specimen, to reduce errors due to slippage of the mounting pins. However, the KGR-1 gage has limited deflection travel (d=0.020 in., see FIG. 1a) and was designed for use in testing of bondline thicknesses (ta) less than 0.040 in. and therefore cannot be used for testing of thick bondlines.
This disclosure is directed toward overcoming one or more problems or disadvantages associated with the prior art.